Weighing device

ABSTRACT

A device for static or dynamic weighing of railway guided vehicles comprising a weigh rail adapted to replace a section of the normal rails with the weigh rail being supported at its ends independent of the adjacent rails and with shear sensing strain gages along the side surfaces of the rail and arranged on the neutral axis of the rail for sensing the load applied to the rail. The device may further include start and stop measuring gages on the weigh rail, an arrangement for providing side guiding of the weigh rail, a structural beam foundation for the weigh rail and spacer means for maintaining the spacing of the adjacent rail ends.

United States Patent [1 1 Nordstrom et al.

1 June 26, 1973 WEIGHING DEVICE I [76] Inventors: Kiellllelge NordstrolmAvsynargat 15; Rune Nils Allan Flinth, Rottargat 2, both of Vesteros,Sweden [22] Filed: Oct. 13, 1971 [21] Appl. No.: 188,957

[52] US. Cl. 177/163 [51] Int. Cl 601g 21/22 [58] Field of Search177/134, 136, 163,

[56] References Cited UNITED, STATES PATIENTS 3,155,184 11/1964Raskin... 177/163 3,085,642 4/1963 Raskin 177/134 3,347,326 10/1967Raskin 177/163 3,554,025 1/1971 Andersson et a1....... 177/211 X3,642,081 2/1972 Hebert 177/163 3,159,227 Raskin et a1; 177/163 FOREIGNPATENTS OR APPLICATIONS 950,493 9/1949 France 177/163 PrimaryExaminer-George H. Miller, Jr.

Attorney-Yount & Tarolli [5 7] ABSTRACT 1 guiding of the weigh rail, astructural beam foundation forthe weigh rail and spacer means formaintaining the spacing of the adjacentrail ends.

17 Claims, 17 Drawing Figures minimum ms mnorz N am an 3 3% wwm WEIGHINGDEVICE This invention relates to weighing devices and, moreparticularly, to a device for the static or dynamic weighing of railwayguided vehicles.

It is well known that weighing of railway guided vehicles can beaccomplished by means of stationary platform scales which are arrangedin weighing pits in the path of the vehicle. Typical of sucharrangements is the provision on the upper surface of the platform of arail of some kind, as for example, a channel beam for a vehicle havingrubber wheels or a rail in the case of rail- .way cars. In eitherinstance, the wheel engaging surface of the rail carried by the platformis in the same plane as the corresponding surface on the fixed groundsupported rails adjacent to the scale but the platform rails aredisconnected from the ground supported rails by an open joint at eitherend so that the rail section carried by the platform scale is free tomove vertically. In such arrangements, the load resting on the scale maybe sensed by various means such as, for example, a mechanical weighingsystem or by the use of load cells.

With scales of this type, the usual requirement of a stiff solidsupportfor the scale has resulted in the use of a massive expensivescale foundation. Because of the size and expense of such scaleinstallations, their use has been restricted to selected fixedlocations. As a result, a need has developed for a scale which isexpensive, can be readily installed at almost any location, canbemoved'to a new location without extensive cost and which will provideacceptable weighing accuracy.

to the deflection of the rail between the adjacent supporting ties. Whenthe train passes over a weighing device which utilizes a massive rigidfoundation, the elastic properties of the relatively-rigidly supportedplatform rails are substantially different from the elastic propertiesof the ground supported rails. The vehicle thus experiences a suddenstiffening of the rail support which substantially reduces the flexingof the rails and entirely eliminates the oscillations due to thedeflection between ties, with the result that the vehicle is, in effect,lifted-up. This in turn causes uncontrolled changes in the verticalforces acting on a vehicle as it is being weighed while in motion.

It has'been proposed to solve the problem of a sudden lift in thevehicle by extending the scale foundation in both directions along thetracks with the foundation gradually-being softened or weakened towardits ends so that a gradual transition is provided between the railssupported on the ties and the rails supported on the rigid foundation.However, this solution has not proven to be satisfactory since even thetransition approaches substantially alter the frequency of oscillationas the vehicle passes. Moreover, the cost of such installations isexcessive.

It is a primary object of this invention to provide a weigh device forthe static or dynamic weighing of railway guided vehicles whichovercomes the foregoing problems, as well as others, and provides aweighing device which is inexpensive to produce and install and providesweighing with acceptable accuracy.

It is a further object of this invention to provide a weigh device whichmay be preassembled in the factory as a unit and installed on site byconventional railway building techniques.

More particularly, in one form of the invention the weigh devicecomprises a weigh rail which is adapted to replace a section of thenormal rail in the railway system with the weigh rail being supported ateither end such that the weigh rail is isolated from axial and bendingforces imposed by the adjacent rails. A pair of shear sensing straingages are spaced along the longitudinal neutral axis of the weigh railand are operative to sense strains due to shear forces in the rails andthereby produce readings which are proportional to the applied load ofthe vehicle.

In accordance with a further aspect of the invention, a structuralmember such as a channel or an I-beam is provided as a foundation forthe weigh rail. with the foundation resting on the sleepers or ties andextending beyond. the weigh rail in both directions. Thefoundationis'designed such that its bending stiffness increases in bothdirectionsto a maximum at the location of the weigh rail and serves todampen the oscillations of the vehicle as it approaches and passes overthe weigh device.

In accordance with a further aspect of the invention, the weigh rail isprovided with start and stop strain sensing gages with the start andstop gages functioning to sense when the wheel of the vehicle passesthereby to start and stop the weighing process.

Other aspects and objects of the invention will be more apparent upon acomplete reading of the following description which, together with theattached drawings, discloses but certain preferred forms of theinvention.

Referring now to the drawings wherein like reference numerals indicatelike parts in the various views:

FIG. 1 is a side elevationalview of a weighing device constructed inaccordance with this invention incorporated in a railway system.

FIG. 1(a) is a sectional view along line 1a-+la of FIG. 1.

FIG. 1(b) is a moment of inertia diagram of the channel foundationemployed in the device of FIG. 1.

FIG. 2 is a side elevation view of a weigh device as a vehicle wheelpasses onto the weigh rail.

FIG. 2(a) is a shear force diagram of the weigh rail of FIG. 2.

FIGS. 2(b) and 2(0) graphically illustrate start and stop signalsgenerated by the start and stop gages as the wheel passes thereover.

FIGS. 2(d) and 2(e) are graphic presentations of the summed outputs ofthe start and stop gages and the summed weight signals, respectively,generated by the strain gages as a vehicle wheel passes thereover.

FIG. 3 illustrates a modified form of the weigh rail.

FIG. 3(a) isa sectional view along line 3a--3a of FIG. 3.

' FIG. 3(b) is a sectional view along line 3b-3b of FIG. 3.

FIG. 4 is a top plan view of a weigh rail incorporated in a railwaysystem and illustrates the manner in which the weigh rail may berestrained to prevent sideways movement.

FIG. 5 is a side elevation view of a modified form of a weigh railsupport.

FIG. 6 is a side elevation view of a weigh device in which an I-beam isused as the foundation.

FIG. 7 is a top plan view of a weigh device and illustrates the mannerin which the adjacent ends of the connecting rails may be restrained byspacer plates.

FIG. 8 is a view along line 88 of FIG. 7.

Referring now more in detail to the drawings, and particularly FIG. 1thereof, a weigh device indicated generally by the reference numeral 10is illustrated as.

it would'be installed in a conventional railway system. The weigh device10 includes a weigh rail 12 which is adapted to replace a section of theusual rail with the weigh rail being aligned with the adjacent ends 14,16 of the conventional rail. The upper surface of the weigh rail 12 iscoplanar with the wheel supporting surface of the adjacent rails toprovide a continuous surface along which the wheel W of a vehicle maypass. However, the ends of the weigh rail 12 are axially separated by asmall space from the adjacent rail ends 14, 16. The weigh rail 12 issupported at its ends by reaction supports Ra, Rb.

The weigh rail 12 has a weigh section which includes a pair of gagedmeasuring sections 18, 20. As shown in FIG. la, the gaged measuringsections of the weigh rail are preferably I-shaped in cross-sectionwhich defines recesses 22, 24 on either side of the rail at eachmeasuringsection. Strain gages 26 are secured to the web of the rail ineach of the recesses at the measuring section 18 and strain gages 28 aresimilarly positioned in each of the recesses at measuring section 20.

As shown in FIG. 2, each of the gages 26, 28 is oriented essentiallyat'45 to the longitudinal neutral axis of the weigh rail 12 so that thestrain gages are operative to sense strains due to shear forces in therails and thereby produce readings which are proportional to the appliedforce F exerted by the wheel W. As will be appreciated, with the gages26, 28 centered on the neutral axis, any strains in the portion of thegages above the axis caused by bending moments is offset or compensatedby strains of opposite polarity and equal magnitude in the portion ofthe gages below the neutral axis. Moreover, by positioning the straingages in therecesses 22, 24, the gages are positioned close to theneutral vertical axis and on either side thereof with the result thatthe weigh device becomes essentially insensitive to horizontal forcesacting transverse to the weigh rail 12.

The weigh rail 12 may also be provided with start and stop measuringgages 30, 32 which are'positioned in the recesses 22, 24 at the gagedmeasuring sections 18, 29 and which may be used to deliver signals whichindicate the start and stop of-the weighing operations as the vehiclewheel W passes over the weigh rail 12. Thus, as the wheel passes overthe gages 30, 32, the shear stress and consequently, the output changespolarity (see FIGS. 2b, 2c and 2d)-and this change in polarity can bevery easily and accurately detected so that a relatively simple startand stop system is provided. Moreover, since the start and stop systemis based on change in polarity, it is insensitive to the direction fromwhich the vehicle wheel approaches the weigh rail 12. Still further, theuse of start and stop gages eliminates the need for any form of railcontacts which cooperate with moving parts on the vehicle.

Also illustrated in FIG. 1 is a U-beam foundation support which may beused with the weigh rail 12. This U- beam foundation comprises a channel36 which rests directly on top of the sleepers or ties 38. Inside thebeam are welded standard type rail mounting plates 40 to which theconventional rails are fixedly secured.

The channel shaped U-beam foundation 36 is also provided with sideflanges 42 which extend longitudinally of the U-beam. The bendingstiffness of the U- beam may be varied by varying the height of theflanges 42. In this manner, the bending stiffness of the U-beamfoundation may be increased from a minimum at either end toa maximumadjacent the weigh rail 12. FIG. 1b graphically illustrates theincreasing moment of inertia of the U-beam foundation.

The described U-beam foundation eliminates the need for excavating andbuilding a foundation as has been the case with prior art systems.Moreover, the relatively high bending stiffness of the U-beam coupledwith its support on a plurality of the sleepers 38 eliminates thepossibility of sudden big vertical deflections of the rail which mightotherwise occur due to a poorly supported sleeper as the wheel passesalong the rail. Still further, the continuously increasing'stiffness ofthe beam also progressively dampens the vertical oscillations of thevehicle as it approaches the weigh rail 12 without drastically alteringthe frequency of the oscillations. To further minimize the verticaloscillations, the sleeper spacings may be decreased along the U-beamfoundation to provide an even more stable support for the weigh device.

It will be apparent that the described weigh device can be readilyinstalled in' any existing railway system using essentially conventionalrailway building techniques. Moreover, the weigh rail 12 can be factoryfabricated and assembled with the foundation in the factory. so that itcan be installed on site very simply and without the need fortechnically trained personnel. If, subsequent to installation, it isdesired for any reason to remove the weigh rail 12, it is but a simplematter to lift the weigh rail 12 out of its assembled location andreplace it with a standard dummy rail so that train service along therailway is not interrupted.

Since the weigh rail 12 merely rests on the reaction supports Ra, Rb ateither end thereof, it is desirable to restrain the weigh rail fromsideways movement thereby to assure continued alignment of the weighrail with the adjacent rail ends 14, 16. This may be accomplished invarious ways with two such techniques being shownin FIG. 4. Asillustrated in that Figure, one end of the weigh rail 12 is providedwith a recess 44 which cooperates with a projecting lug 46 ontheadjacent end 16 of the rail. The cooperation of the recess 44 and lug 46restrain that end of the weighrail from transverse or sideways movement.An alternative arrangement for restraining the weigh rail is illustratedat the other end of weigh rail 12 in which a suitable keeper 48 issecured to the end 14 of the rail and defines a recess in which theweigh rail is received. In addition, a crossconnection 50 having lowresistance to bending and torsion may extend between the weigh rails 12associated with each of the rail tracks. I

Although the weigh rail 12 has been described as being axially spaced asmall distance from the rail ends 14, 16, in practice the rail 12 mayshift longitudinally until it physically abuts one or the other of theends l4, 16 without adversely affecting the weighing operation.

Nor does the frictional engagement between either lug 46 and recess 44or keeper 48 have any significant detrimental effect on the weighingaccuracy of the device. In general, the relationship between the weighrail 12 and rail ends 14, 16 should be such that the rail ends do notexert axial compressive forces which would tend to buckle or bend theweigh section of the weigh rail. Accordingly, although an axial spacebetween rail 12 and rail ends 14, 16 is disclosed, techniques other thana physical axial separation with side guiding may be employed.

It is also to be noted that, although the weigh rail 12 has beendescribed as merely resting in position between the rail ends, it may besecured to the foundation 36 as by welding or by any other suitablemeans.

Referring now to FIGS. 3, 3a and 3b, a weigh rail 12 essentially of thesame construction as that shown in FIG. 1 is illustrated. However, theradius of the wheel engaging surface of the rail has been reduced in themid-section of the weigh rail, as shown at 52 in order to secure acentered loading as the wheel rolls along the weigh rail. The radius ofthe top surface of the rail at either end of the weigh rail 12' has beenmaintained the same as the adjacent ends 14, 16 to avoid transitionproblems at the connecting rail interfaces. 1

A modified form of weigh rail support is illustrated in FIG. 5 wherein apair of pedestal supports 54 support the weigh' rail 12' at itslongitudinal neutral axis. This arrangement of supporting the rail atits neutral axis has the advantage of eliminating undesired second orderbending effects.

While a channel shaped foundation 36 is the preferred arrangement, otherstructural shapes may be used, if desired. For example, FIG 6illustrates the use of an I-beam 56 which is positioned in a shallowexcavation beneath the rails and, if desired, rests on ties or sleepers.As in the embodiment of FIG. 1, the height of the I-beam is tapered fromboth ends to provide a foundation with increasing bending stiffness withthe maximum in the area of the weigh rail.

FIGS. 7 and 8 illustrate the use of the weigh rail 12 without anystructural foundation support. As illustrated in FIG. 8, the weigh rail12 rests directly on flat plates 60 which in turn are supported on thesleepers 38. A pair of spacer plates 62, 64 interconnect the rail ends14, 16. The spacer plates serve to restrain the rail ends againstlongitudinal movement which might otherwise occur due to thermalexpansion and contraction and thereby prevent the application ofcompressive forces to the rail 12. It is preferred that the plates 62,64 have a moment of inertia which generally coincides with that of railsl4, 16 so that their resistance to bending is similar to that of therails.

The plates 62, 64 may also be provided with notched openings 66 whichcooperate with the ends of weigh rail 12 to provide lateral restraintfor the weigh rail and maintain it in alignment with the two rail ends.

While the invention has been described with particular reference tocertain embodiments, neither the illustrated embodiments nor theterminology employed in describing them is intended to be limiting;rather, it is intended to be limited onlyby the scope of the appendedclaims.

Having thus described the invention, what is claimed is:

l. A weigh device for weighing of railway guided vehicles comprising aweigh rail adapted to be operatively associated with the rails in arailway system,

gage means connected to said weigh rail at spaced locations therealongwith said gage means being arranged to sense the strain in said weighrail due to shear forces and produce signals proportional to the loadapplied to said weigh rail, and

indicator gage means being arranged to sense the strain in said weighrail due to shear forces whereby the signal produced by said indicatorgage means is operative to produce a signal indicative of a wheel of avehicle passing thereover by a change in polarity of the signal as awheel passes.

2. The weigh device of claim 1 wherein said indicator strain gage meanscomprise a pair of indicator gage means positioned between said spacedgage means for signalling the start and stop of the weighing operation.

3. A system for weighing railway guided vehicles comprising alongitudinally extending rail means adapted to cooperate with andsupport the wheel of a railway vehicle,

a plurality of ground support ties underlying and extending transverseto said rail means for supporting said rail means,

said rail means including longitudinally spaced apart first and secondrail sections defining a space therebetween, I

a weigh device having at least a portion thereof positioned in the spacebetween said sections,

foundation means supported on said ground support ties with said firstand second sections and said portion of said weigh device supported bysaid foundation means, and

means rigidly interconnecting said first and second sections to saidfoundation means for restraining longitudinal movement of said sections.

4. The system of claim 3 wherein said foundation means comprises a pairof spacer plates secured to said first and second sections on eitherside thereof.

5. A system for weighing railway guided vehicles comprising:

longitudinally extending rail means adapted to cooperate with andsupport the wheels of a railway vehicle,

a plurality of individual spaced apart ground supports extendingtransversely to and underlying said rail means,

a weigh device operatively associated with a portion of said rail means,and

a longitudinally extending structural beam foundation,

said beam foundation being positioned beneath said portion of said railmeans and extending longitudinally in both directions therefrom withsaid beam foundation being supported on said ground supports andsupporting said weigh device.

6. The system of claim 5 wherein said beam foundation is generallychannel shaped.

7. The system of claim 5 wherein said beam foundation comprises anI-beam. I

8. A system for weighing railway guided vehicles including:

longitudinally extending rail means adapted to cooperate with andsupport the wheels of a railway vehicle,

a plurality of spaced apart support ties underlying and extendingtransverse to said rail means,

said rail means including longitudinally spaced apart first and secondrail sections defining a space therebetween,

weigh rail means positioned in the space between said first and secondrail sections,

means operatively supporting said weigh rail means at either end thereofon said support ties,

said weigh rail means including a weigh section having a pairoflongitudinally spaced apart shear sensing gage means secured to saidweigh rail means with said gage means being arranged to sense the strainin said weigh rail means due to shear forces as the vehicle wheel passesthereover, and

means restraining longitudinal movement of said adjacent rail ends forprotecting said weigh rail means from being subjected to longitudinalcompressive forces exerted by said adjacent rail ends.

9. The system of claim 8 and further including start and stop straingages longitudinally spaced along and secured to said weigh rail means,

said start and stop strain gages being operative to produce anelectrical signal indicating the passage of a vehicle wheel thereover.

10. The system of claim 8 wherein the wheel supporting surface of saidweigh rail has a reduced radius along the mid-portion thereof. a 1

11. The system of claim 8 wherein said weigh rail has an l-shapedcross-section at least at the locations of said strain gages with saidstrain gages being secured to the web portion formed by said I-shapedcross-section.

12. The system of claim 8 and further including means co-operating withsaid weigh rail means to restrain movement of said weigh rail meanstransversely of said first and second rail sections.

13. The system of claim 8 wherein said means for preventing said weighsection includes spacer means secured to and interconnecting theadjacent ends of said first and second rail sections.

14. The system of claim 8 wherein said means for protecting said weighsection comprises a space defined between at least one end of said weighrail means and the adjacent rail end.

15. The system of claim 8 wherein said support means support said weighrail means at its longitudinal neutral axis.

16. The system of claim 8 wherein said means operatively supporting saidweigh rail means comprises structural foundation means supported on saidties and extending longitudinally of and supporting the adjacent ends ofsaid first and second rail stations and said weigh rail means.

17. The system of claim 16 wherein said structural foundation means ischannel shaped and constructed to have a moment of inertia whichprogressively increases towardthe location of said weigh rail.

1. A weigh device for weighing of railway guided vehicles comprising aweigh rail adapted to be operatively associated with the rails in arailway system, gage means connected to said weigh rail at spacedlocations therealong with said gage means being arranged to sense thestrain in said weigh rail due to shear forces and produce signalsproportional to the load applied to said weigh rail, and indicator gagemeans being arranged to sense the strain in said weigh rail due to shearforces whereby the signal produced by said indicator gage means isoperative to produce a signal indicative of a wheel of a vehicle passingthereover by a change in polarity of the signal as a wheel passes. 2.The weigh device of claim 1 wherein said indicator strain gage meanscomprise a pair of indicator gage means positioned between said spacedgage means for signalling the start and stop of the weighing operation.3. A system for weighing railway guided vehicles comprisinglongitudinally extending rail means adapted to cooperate with andsupport the wheel of a railway vehicle, a plurality of ground supportties underlying and extending transverse to said rail means forsupporting said rail means, said rail means including longitudinallyspaced apart first and second rail sections defining a spacetherebetween, a weigh device having at least a portion thereofpositioned in the space between said sections, foundation meanssupported on said ground support ties with said first and secondsections and said portion of said weigh device supported by saidfoundation means, and means rigidly interconnecting said first andsecond sections to said foundation means for restraining longitudinalmovement of said sections.
 4. The system of claim 3 wherein saidfoundation means comprises a pair of spacer plates secured to said firstand second sections on either side thereof.
 5. A system for weighingrailway guided vehicles comprising: longitudinally extending rail meansadapted to cooperate with and support the wheels of a railway vehicle, aplurality of individual spaced apart ground supports extendingtransversely to and underlying said rail means, a weigh deviceoperatively associated with a portion of said rail means, and alongitudinally extending structural beam foundation, said beamfoundation being positioned beneath said portion of said rail means andextending longitudinally in both directions therefrom with said beamfoundation being supported on said ground supports and supporting saidweigh device.
 6. The system of claim 5 wherein said beam foundation isgenerally channel shaped.
 7. The system of claim 5 wherein said beamfoundation comprises an I-beam.
 8. A system for weighing railway guidedvehicles including: longitudinally extending rail means adapted tocooperate with and support the wheels of a railway vehicle, a pluralityof spaced apart support ties underlying and extending transverse to saidrail means, said rail means including longitudinally spaced apart firstand second rail sections defining a space therebetween, weigh rail meanspositioned in the space between said first and second rail sections,means operatively supporting said weigh rail means at either end thereofon said support ties, said weigh rail means including a weigh sectionhaving a pair of longitudinally spaced apart shear sensing gage meanssecured to said weigh rail means with said gage means being arranged tosense the strain in said weigh rail means due to shear forces as thevehicle wheel passes thereover, and means restraining longitudinalmovement of said adjacent rail ends for protecting said weigh rail meansfrom being subjected to longitudinal compressive forces exerted by saidadjacent rail ends.
 9. The system of claim 8 and further including startand stop strain gages longitudinally spaced along and secured to saidweigh rail means, said start and stop strain gages being operative toproduce an electrical signal indicating the passage of a vehicle wheelthereover.
 10. The system of claim 8 wherein the wheel supportingsurface of said weigh rail has a reduced radius along the mid-portionthereof.
 11. The system of claim 8 wherein said weigh rail has anI-shaped cross-section at least at the locations of said strain gageswith said strain gages being secured to the web portion formed by saidI-shaped cross-section.
 12. The system of claim 8 and further includingmeans co-operating with said weigh rail means to restrain movement ofsaid weigh rail means transversely of said first and second railsections.
 13. The system of claim 8 wherein said means for preventingsaid weigh section includes spacer means secured to and interconnectingthe adjacent ends of said first and second rail sections.
 14. The systemof claim 8 wherein said means for protecting said weigh sectioncomprises a space defined between at least one end of said weigh railmeans and the adjacent rail end.
 15. The system of claim 8 wherein saidsupport means support said weigh rail means at its longitudinal neutralaxis.
 16. The system of claim 8 wherein said means operativelysupporting said weigh rail means comprises structural foundation meanssupported on said ties and extending longitudinally oF and supportingthe adjacent ends of said first and second rail stations and said weighrail means.
 17. The system of claim 16 wherein said structuralfoundation means is channel shaped and constructed to have a moment ofinertia which progressively increases toward the location of said weighrail.